gistfile1.txt

# old way: 
   func = dlfunc lib, "foo", "vilf"

Limited by the string. New types aren't available, and aliasing types doesn't work. Structures are difficult too. 


# New way:
constants:

   c_void       = c void
   c_char       = c int8
   c_wchar      = c_sint16 or c_int32 # system dependent 
   c_byte	    = c_sint8
   c_ubyte	    = c_uint8
   c_short	    = c_sint16
   c_ushort	    = c_uint16
   c_int        = c_long    = c_sint32
   c_uint       = c_ulong   = c_uint32 
   c_longlong	= c_sint64 # __int64 or long long	int/long
   c_ulonglong  = c_uint64 # unsigned __int64 or unsigned long long	int/long
   c_float	    # float
   c_double	    # double	float
   c_longdouble	# long double	float  system dependent 

# connivence consts:
   c_char_p	    # char * (NUL terminated)	string or None
   c_wchar_p	# wchar_t * (NUL terminated)	unicode or None
   c_void_p	    # void *	int/long or None
   
# functions: 
PMC pointer(PMC type_constant) # finds the pointer value of a constant type
PMC byref(PMC ref_value)   # finds makes a reference for function calls
PMC array(PMC type_constant, INT size) # creates a new array of type_constant type of size length
PMC newstruct 'name'
INT sizeof(PMC type or value)
PMC cast(PMC value, PMC type_constant)

# Example:

# C Example:

struct in_addr
{
    unsigned long s_addr;
};

struct sockaddr_in
{
  short   sin_family; /* must be AF_INET */
  u_short sin_port;
  struct  in_addr sin_addr;
  char    sin_zero[8]; /* Not used, must be zero */
};

pin.sin_family = AF_INET;
pin.sin_addr.s_addr = ((struct in_addr *)(hp->h_addr))->s_addr;
pin.sin_port = htons(PORT);

/* grab an Internet domain socket */
if ((sd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
	perror("socket");
	exit(1);
}

/* connect to PORT on HOST */
if (connect(sd,(struct sockaddr *)  &pin, sizeof(pin)) == -1) {
	perror("connect");
	exit(1);
}


# Potential parrot equivalent: 


$P0 = newstruct 'in_addr'
$P0['s_addr'] = c_ulong

$P1 = newstruct 'sockaddr_in'
$P1['sin_family'] = c_short
$P1['sin_port'] = c_ushort
$P1['sin_addr'] = $P0
$P1['sin_zero'] = array(c_char, 8)

$P2 = new $P1
$P2['sin_family'] = AF_INET # constant defined somewhere else
$P3 = pointer('in_addr')
$P4 = cast($P123, $P3) # $P123 given defined somewhere else
$P2['sin_addr';'s_addr'] = $P4['s_addr']

$P2['sin_port'] = 1234
                            # return, #param1 ... n 
$P5 = dlfunc lib, 'socket', c_int   , c_int, c_int, c_int

$P6 = $P5(AF_INET, SOCK_STREAM, 0) # constants defined elsewhere 

# connect signature: int connect(int, struct sockaddr *address, socklen_t address_len); socklen_t = int (assuming)
$P7 = dlfunc lib, 'connect', c_int, c_int, c_void_p, c_int) 

$P8 = pointer($P2)
$P9 = byref($P2)
$I1 = sizeof($P2)

$P7($P6, $P9, $I1) # invoke connect(int, struct sockaddr *address, socklen_t address_len)